Hi guys ! Don't know if this is ok to post here. I am building a new bobber with the 93ci knucklehead motor. Paughco hard-tail frame. Springer front-end with shock. Trying to build a late 40's early fifties style racer. Stripped down lean and mean. I am going kick only, and tank shift with rocker clutch. The only concession is disc brakes. stopping is very important. I have always wanted a knucklehead, and although not original I hope a beautiful tribute to a beautiful design.

I have had a similar project growing in my garage for a couple years. I'm not a fan of Paughco frames as the look so, well so aftermarket. I used a V-twin reproduction frame. It took a little time to fix the minor wrongs with it. STD cases. S&S interior parts. FHP Big Bore barrels. Genuine H-D heads, valve train and timing gear cover. Electric start. Genuine XA Springer. '69 rear hydraulic brake. Gonna have a disc in front.Here it is as being dry assembled now.

That is truly a work of art ! I hope mine will turn out as well. I am using the paughco frame that appears more stock looking. Not the chopper style. What it lacks in eye appeal though it is Strong. It was built just for my motor. All the welds were beefed-up.

Chris Haynes wrote:But still when someone gets within 15 feet of your bike they say, "Oh, a Paughco frame".

Never "Oh, STD cases...." or "Eeeuuw, electric start" when they get 15 yards from your project, Chris?Disc brakes are always real authentic.

I only need to look at a carb before I cop an attitude!

....CottenPS: I'm not disparaging S&S carbs by any means. They are fine modern carbs.

It's a good thing I am using a genuine H-D carb then isn't it Cotten. Do you see the electric start on my bike? I have a one off set of STD cases. All drilled for a Knucklehead, Timkem bearings, machined for 1965-1969 outer primary cover. The only set like it they ever made. S&S wouldn't make them for me. With a 93" engine and high speed riding I sure don't want my life to depend on mechanical brakes. This bike is a street rod, not a restoration.

Cotten, I've wanted to ask you forever, and your modern carb line finally got me to ask, not that I'm a fan of S&S carbs particularly. Hearing you talk about the reservoir of fuel acting as a accelerator pump, and all the other minutiae of the linkert design, I'm thinking if ever anyone got a linkert properly tuned on a harley, you have. Anyway, here's the question: My experience with linkerts ended years ago, before I knew about, (from you) how to detect and fix manifold leaks.When riding a harley with a Linkert, even the DC, the machines always tended to "8stroke" at light load at low, but above idle, engine speeds, going down the road. I.E, you're in town, doing 25-30, probably 2-3 gear, and the engine is running rich and doing what I call "8 stroking", not firing evenly. And I hear many, many h-ds' do this, on a variety of carbs. But, I could never get a Linkert to not do this. To be fair the The DC's and the SU's did it too. With the VM Mikuni's (and tight manifolds, thanks to you) I can tune to eliminate this annoying trait.Was it just me? Had I the patience and a carb you had returned to as new condition, could this problem be solved? I'm really only out for knowledge with this question, you can tell, I hope, because I've tried to be so polite in phrasing it and not used the usual expletive laced language I normally use towards Brass linkerts!

Frankenstein wrote:Cotten, I've wanted to ask you forever, and your modern carb line finally got me to ask, not that I'm a fan of S&S carbs particularly. Hearing you talk about the reservoir of fuel acting as a accelerator pump, and all the other minutiae of the linkert design, I'm thinking if ever anyone got a linkert properly tuned on a harley, you have. Anyway, here's the question: My experience with linkerts ended years ago, before I knew about, (from you) how to detect and fix manifold leaks.When riding a harley with a Linkert, even the DC, the machines always tended to "8stroke" at light load at low, but above idle, engine speeds, going down the road. I.E, you're in town, doing 25-30, probably 2-3 gear, and the engine is running rich and doing what I call "8 stroking", not firing evenly. And I hear many, many h-ds' do this, on a variety of carbs. But, I could never get a Linkert to not do this. To be fair the The DC's and the SU's did it too. With the VM Mikuni's (and tight manifolds, thanks to you) I can tune to eliminate this annoying trait.Was it just me? Had I the patience and a carb you had returned to as new condition, could this problem be solved? I'm really only out for knowledge with this question, you can tell, I hope, because I've tried to be so polite in phrasing it and not used the usual expletive laced language I normally use towards Brass linkerts!

Dr. Dick!

This will be hard for me to reply , as the format keeps changing, and will not allow me to see what I am typing, as I am typing it! (And where did the attachment tab go?) Logging in and out does not help.

I do not believe any design of carb is a bad one, and I only prefer classic models because they are simple. Modern carbs are un-necessarily over-complicated."8-stroking" is a term that have never heard, and I do not know if I have ever experienced it. If I did, I always fixed it.

I would type more, but every keystroke automatically scrolls back up to the middle of the post!Is there a button for that?

Now I can continue my reply, but there's still no attachment tab like I see in other forum headings....

As far as " if ever anyone got a linkert properly tuned on a harley, you have.", I can only say that it is the rider who tunes the carb! When everything is in order, any necessary compensation for changes in fuel, altitude, climate, etc. are merely a little trial and error with the needles.

So my suspicion is that this curious "8stroke" phenomenon would be that it results from small vacuum leaks.Sealing the tiniest of leaks can make a machine that ran "fine", run "like a brand new machine".

Or maybe we are talking about the pesky "flat spot" between idle circuit speeds and power circuit speeds?

That can originate at a shrunken venturi, excessive borewear at the throttle disc, or from vacuum leakage at the shaft bushings, or warped manifold flanges, or at the metering spring collar, or all of the above.

So my conviction is that Linkerts get a bad reputation from generations of poor maintenance and wear, resulting from extended service allowed by their very forgiving nature!

....CottenUh oh, I hit another wrong button on this damn laptop, and its doing it again! cntr+?

Frankenstein wrote:Cotten, I've wanted to ask you forever, and your modern carb line finally got me to ask, not that I'm a fan of S&S carbs particularly. Hearing you talk about the reservoir of fuel acting as a accelerator pump, and all the other minutiae of the linkert design, I'm thinking if ever anyone got a linkert properly tuned on a harley, you have. Anyway, here's the question: My experience with linkerts ended years ago, before I knew about, (from you) how to detect and fix manifold leaks.When riding a harley with a Linkert, even the DC, the machines always tended to "8stroke" at light load at low, but above idle, engine speeds, going down the road. I.E, you're in town, doing 25-30, probably 2-3 gear, and the engine is running rich and doing what I call "8 stroking", not firing evenly. And I hear many, many h-ds' do this, on a variety of carbs. But, I could never get a Linkert to not do this. To be fair the The DC's and the SU's did it too. With the VM Mikuni's (and tight manifolds, thanks to you) I can tune to eliminate this annoying trait.Was it just me? Had I the patience and a carb you had returned to as new condition, could this problem be solved? I'm really only out for knowledge with this question, you can tell, I hope, because I've tried to be so polite in phrasing it and not used the usual expletive laced language I normally use towards Brass linkerts!

Dr. Dick!

This will be hard for me to reply , as the format keeps changing, and will not allow me to see what I am typing, as I am typing it! (And where did the attachment tab go?) Logging in and out does not help.

I do not believe any design of carb is a bad one, and I only prefer classic models because they are simple. Modern carbs are un-necessarily over-complicated."8-stroking" is a term that have never heard, and I do not know if I have ever experienced it. If I did, I always fixed it.

I would type more, but every keystroke automatically scrolls back up to the middle of the post!Is there a button for that?

....Cotten

Cotten,I brought the attachment tab glitch to S&S's attention. This scrolling back issue is new. It is doing it to me also. My guru is no longer employed at S&S but he subcontracts to them when solicited. Hopefully, they will subcontract him to fix these problems. Pa

Cotten, Sorry about the terminology,I guess I just invented the 8 stroking the morning! Plain language, it just "burbles", runs rich, and I'm guessing it is the transition period between metering systems, as well as the other points of wear,abuse, which you refer to. I guess the Linkert is a lot like the old Harley it was bolted to, able to take a lickin' and still keep tickin' , after a fashion By the by, I'm not having any particular problems this morning with typing in the windows. Seems to behave as normal. Using Firefox, don't know if it matters.Dick

Whenever "running rich" is a problem, I once again suspect a vacuum leak.

My logic is that the carb is over-enrichened to make up for extra air, or it won't run at all!

Please remember that no two leaks behave the same (except those that prevent the machine from even starting), and variables such as varying vacuum at varying RPM, etc., make them hard to sort out.So my approach is eliminate all possibilties of a leak, absolutely.No leak is acceptible, no matter how small.Obviously, modern carbs have added bells and whistles to allow some tuning "around" leaks that were never detected.